Upper Mill Creek Canyon will briefly reopen Monday after 7 months of construction. Here’s a sneak peek.

Plastic hard hats protected construction workers in Upper Mill Creek Canyon this summer. They also protected the fish.

The upper canyon is undergoing a $38 million improvement project that is a collaboration among the Forest Service, Salt Lake County and the city of Millcreek. It entails widening the road to create better access for emergency vehicles, adding off-street parking and other amenities and reducing erosion. The 4.6-mile section of the road has been closed since May 1, during which crews have installed or repaired nine bridges and will expand it by some 45 acres.

Throughout the process, project manager Shelby McCune said his crews have gone to great lengths to ensure Upper Mill Creek Canyon retains its magic. In fact, it’s McCune’s goal that when the canyon temporarily reopens for nonmotorized winter activities — which it will Monday through March 15 — that users will barely be able to tell workers were there.

“When we leave, we won’t leave cones,” said McCune, a partner at the Lindon-based construction company S&L Inc. “When the snow piles in here, we want it to look natural as much as we can. So there’ll be piles of dirt in various places, but there’ll be no equipment left here, no orange cones or fences that don’t look like they need to be there.”

Some changes will be obvious, though, even to infrequent visitors.

Among them is a broad, 28-foot tall retaining wall that has been built on the north side of the canyon between the White Bridge and Elbow Fork. Currently slate grey and smooth, McCune said it will be covered with another layer of shotcrete and textured during the final phase of construction next year to make it blend more seamlessly with its environment. The inspiration will be a yellow-and-brown-hued natural rock wall just above Elbow Fork that had to be chipped back some to widen the road.

Even before visitors get to the wall, they’ll notice the nearly century-old White Bridge is in the middle of being replaced. Travelers will pass alongside it over a temporary, paved road. However, crews carefully sliced off the old bridge’s stone railing — which dates back to 1937, when it was built by the Civilian Conservation Corp — and they plan to display it in the new, adjacent parking lot.

“The way I described it — how we’ve been really making sure our crew understands it — is:“ McCune said of preservation efforts, “This is a park five miles long that happens to have a road in it.”

Also unmistakable are the one other new and two enlarged parking lots that have sprung up along that road.

“One of the main ideas behind the project was to formalize parking,” said Brock Damjanovich, a spokesperson for the Salt Lake County Office of Regional Development. “Because it was parking on the side of the road that was causing a ton of congestion.”

A new, 30-car lot is being built just below Elbow Fork on the south side of the road. It will replace the parking at the bend, where hikers can access the Mount Aire and Terraces trails, among others. That lot will have bathrooms and will be directly across the road from a new connector trail that leads to the popular Pipeline Trail.

Meanwhile, the Alexander Basin and Big Water lots will all be made larger.

Alexander Basin’s lot will be paved and add about five new spots, for a total of 20, plus a vault toilet, according to the project’s environmental assessment. Big Water, at the end of the road, is planned to more than double in size (from 32 to 71 parking spots) and add a pick-up and drop-off area. It will eventually be fitted with new vault toilets as well.

McCune said that near the end of the project, 870 boulders that were unearthed during excavation will be placed along the roadside to discourage parking outside of designated lots and spaces.

Those are the kinds of changes, along with several missing trees and a few remaining piles of dirt, that McCune said he thinks people will notice this winter. What they may not see right away, he said, is the stones carefully placed flat side up to make them better seats and bridges, or the carefully crafted fishing holes.

“They’ve really thought about how some of that stuff will work,” McCune said of his crew, “and how it will shape, and where the fish would hide. We really try to think about that.”

Perhaps the most interesting example of the extent to which McCune and his crew had tried to preserve the canyon won’t be seen by visitors at all.

To install the bridges, most of which are connected with the parking areas, workers had to work around Mill Creek. Often, they installed a wide diversion pipe, through which the creek could temporarily run around work sites. Sometimes, though, it had to be pumped to a different location.

On those occasions, the creek’s fish would get stranded in the lowest pools, which McCune said would be blocked with a fish screen. So several times a day, construction workers would go down to the creek and dip buckets — or, just as often, their hard hats — into the water to collect the stuck fish. Then they’d carry them upstream and release them back into the creek, only to have to repeat the process the next day.

It goes to show, Damjanovich said, that “preserving the charm of this canyon is [priority] No. 1.”

Construction in Upper Mill Creek is about 60% completed, McCune said. He added, however, that most of the biggest projects are well under way. That includes installing data cables that should enable a shuttle to one day traverse the canyon.

The canyon will close again on March 15 and will be closed through December 2026, at which point all work is scheduled to be completed.